U.S. patent number 4,474,933 [Application Number 06/500,597] was granted by the patent office on 1984-10-02 for crosslinking resin mixtures.
This patent grant is currently assigned to Dynamit Nobel AG. Invention is credited to Gerhard Geier, Eduard Hansel, Hans Huber.
United States Patent |
4,474,933 |
Huber , et al. |
October 2, 1984 |
**Please see images for:
( Certificate of Correction ) ** |
Crosslinking resin mixtures
Abstract
The present invention relates to resin mixtures which are fluid
at temperatures up to 100.degree. C. and which crosslink either at
elevated temperature or under the influence of moisture. Thermal
crosslinking takes place at temperatures of 100.degree. C. and up,
preferably at about 120.degree. C. The mixtures contain one or more
mutually compatible polymers containing hydroxyl groups, in which
at least 5% and not more than 90% of the hydroxyl groups are
replaced by alkoxysilyl groups. The introduction of the alkoxysilyl
groups is accomplished by the reaction of a diisocyanate with a
hydroxyl group on the polymer, on the one hand, and with an
aminosilane or mercaptosilane ester on the other. On the basis of
their fluid-to-viscous consistency at room temperature or
moderately elevated temperature, the resins can be applied in a
thin coating and easily crosslinked in situ.
Inventors: |
Huber; Hans (Troisdorf-Spich,
DE), Hansel; Eduard (Dusseldorf, DE),
Geier; Gerhard (Lohmar, DE) |
Assignee: |
Dynamit Nobel AG (Cologne,
DE)
|
Family
ID: |
6165173 |
Appl.
No.: |
06/500,597 |
Filed: |
June 2, 1983 |
Foreign Application Priority Data
Current U.S.
Class: |
528/26; 525/457;
528/25; 528/30; 556/450; 556/458; 428/149; 528/22; 528/29; 528/38;
556/457; 556/459 |
Current CPC
Class: |
C08G
18/778 (20130101); C08G 18/718 (20130101); C08G
18/809 (20130101); Y10T 428/24421 (20150115); C08G
2150/20 (20130101); C08G 2170/20 (20130101) |
Current International
Class: |
C08G
18/80 (20060101); C08G 18/71 (20060101); C08G
18/77 (20060101); C08G 18/00 (20060101); C08G
077/04 () |
Field of
Search: |
;528/22,25,26,29,30,38
;556/450,457,458,459 ;428/149 ;525/457 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Marquis; Melvyn I.
Attorney, Agent or Firm: Felfe & Lynch
Claims
What is claimed is:
1. A crosslinkable resin mixture which is liquid at temperatures
below 100.degree. C., is made from polymers containing hydroxyl
groups and having a molecular weight of 500 to 30,000, and wherein
5 to 90 mol.-% of the hydroxyl groups originally present in the
mixture have been replaced by the reaction product of an
organosilane of the general formula ##STR4## wherein R.sub.1 =H or
alkyl, cycloalkyl, aryl or aralkyl, R.sub.2 =C.sub.1 -C.sub.5
alkylene, R.sub.3 =methyl or ethyl, R.sub.4 =alkyl or
alkoxyalkylene of up to 4 carbon atoms, and n=0 or 1 or 2, with a
monomeric or polymeric di- or triisocyanate.
2. The crosslinkable resin mixture of claim 1, wherein the polymers
contained in the mixture contain terminal or randomly distributed
hydroxyl groups as well as groupings of the general formula
##STR5## wherein R.sub.x =residue of the monomeric or polymeric
diisocyanate that was used for the preparation.
3. The crosslinkable resin mixture of claim 1, characterized in
that its setting is brought about by reaction with water or
atmospheric humidity or by heating to temperatures of 100.degree.
C. or higher.
4. The crosslinkable resin mixture of claim 3 wherein the
temperature to which it is heated is at least 120.degree. C.
5. The crosslinkable resin mixture of claim 1 further comprising a
catalyst for accelerating the setting time of the adhesive.
6. The crosslinkable resin mixture of claim 1 wherein the polymers
have a molecular weight in the range of 1000 to 10,000.
7. The crosslinkable resin mixture of claim 1 wherein 10% to 80
mole-% of the hydroxy group have been replaced.
8. The crosslinkable resin mixture of claim 1 wherein the polymer
is selected from the group consisting of polyester polyols,
polyether polyols, polyether ester polyols, functional glycerides,
partial glycerides, polybutadienes containing hydroxyl group, and
poly(meth)acrylic acid ester copolymers; and having a point (Tg) of
less than 20.degree. C.
9. The crosslinkable resin mixture of claim 8 wherein the polymer
is castor oil or ricinic monodiglyceride.
10. The crosslinkable resin mixture of claim 1 wherein the
organosilane is
gamma-aminopropyltrimethoxysilane,
gamma-aminopropyltriethoxysilane,
N-methyl-gamma-aminopropyltrimethoxysilane,
N-n-octyl-gamma-aminopropyltrimethoxysilane,
N-phenyl-gamma-aminopropyltrimethoxysilane,
N-methyl-gamma-aminopropylmethyldimethoxysilane,
gamma-mercaptopropyltrimethoxysilane, or
gamma-mercaptopropyltriethoxysilane.
11. The crosslinkable resin mixture of claim 2 wherein the
component of the resin mixture which contains the terminal group is
selected from the group consisting of
an adduct of
3-isocyanatomethyl-3,5,5-trimethyl-cyclohexyl-isocyanate, with
N-methyl-gamma-aminopropyltris-methoxydiglycol-silane,
gamma-mercaptopropylsilane,
N-methyl-gamma-aminopropyltrimethoxysilane,
N-methyl-gamma-aminopropylmethyldimethoxysilane, or
N-n-octyl-gamma-aminopropyltrimethoxysilane;
an adduct of toluyl diisocyanate with
N-methyl-gamma-aminopropyltrimethoxysilane; and
an adduct of methylene-bis-phenylisocyanate and
N-methyl-gamma-aminopropyltrimethoxysilane.
12. A crosslinkable resin mixture which is liquid at temperatures
below 100.degree. C., from polymers containing hydroxyl groups and
having a molecular weight of 500 to 30,000, and wherein 5 to 90
mol.-% of the hydroxyl groups originally present in the mixture
have been replaced by the reaction product of
with a monomeric or polymeric di- or triisocyanate.
Description
BACKGROUND OF THE INVENTION
The subject of the present invention is crosslinking resin mixtures
which are liquid at temperatures under 100.degree. C. and are
prepared on the basis of polymers containing hydroxyl groups and
having a molecular weight of 500 to 20,000.
It is known that alkoxysilanes react readily with moisture. This
tendency toward hydrolysis is useful in many ways, the
adhesion-mediating action of the organosilanes between different
kinds of materials being worthy of special note (see "Handbook of
Adhesives", 2nd Edition, by Irving Skeist, pp. 640 sqq., Van
Nostrand-Reinhold Co., 1977).
The hydrolysis of the alkoxysilanes with the formation of siloxane
bonds has also been widely used for the crosslinking of polymers.
In DE-OS No. 2,314,757 there is described a binding agent of which
at least 50% by weight consists of a copolymer having lateral
alkoxysilane groups. U.S. Pat. No. 4,291,136 describes a
water-hardening, silane-modified alkylene-alkyl acrylate copolymer.
Such copolymers, however, must be fabricated either from solution
in organic solvents or with machines commonly used for plastic
fabrication, such as extruding machines.
Attempts have already been made to produce liquid polymers
containing no solvents, which can be crosslinked by the addition of
water or by reaction with atmospheric moisture. In U.S. Pat. No.
3,632,557, the starting products are liquid polymers having
terminal hydroxyl groups, which are transformed by reaction with
excess diisocyanate to a polymer having terminal isocyanate groups.
These are then reacted with an aminosilane, preferably
gamma-aminopropyltrimethoxysilane, so that finally a liquid polymer
results which is provided stoichiometrically, i.e., quantitatively,
with alkoxysilyl terminal groups. Such liquid polymers set with
atmospheric moisture to form rubber-like products which, however,
suffer from a number of undesirable properties, as described very
extensively in U.S. Pat. No. 3,971,751. Their poor elongation at
rupture, and above all their extremely poor resistance to continued
tearing, are serious disadvantages, and is found to a more or less
great extent in all such materials which are terminated
stoichiometrically with alkoxysilyl groups. This is equally true of
the products described in U.S. Pat. Nos. 3,979,344 and 4,222,925.
This disadvantage is largely overcome by the procedure described in
U.S. Pat. No. 2,971,751; the process therein described, however, is
so complex that the results described can be obtained better, and
especially much more simply, by other methods.
The reactivity of alkoxysilanes with the hydroxyl groups of
polymers containing hydroxyl rather than with water is utilized in
the method that is the basis of Japanese Pat. No. 56084751: liquid
polymers with terminal hydroxyl groups are hardened with
alkoxysilanes at elevated temperature (150.degree. C.) and elevated
pressure (150 bar) to form elastomeric moldings. This process can
be performed only with the application of pressure because, at the
temperatures at which the transesterification is performed, the
alkoxysilanes otherwise would volatilize and thus would be unable
to act. For applications in which the material is in a thin layer,
as for example in any kind of coatings, varnishes, glues, etc.,
this technology is entirely inapplicable.
BRIEF DESCRIPTION OF THE INVENTION
The present invention is addressed to the problem of preparing
mixtures which can be processed in the liquid state at room
temperature or at moderately elevated temperature (i.e., under
100.degree. C.), applied as a coating, and then can be transformed
by crosslinking to a state of substantially higher consistency. The
use of organic solvents should be restricted to a minimum or,
better, entirely eliminated.
It has now been found that this problem can be solved by using
fluid polymers containing hydroxyl groups and replacing the
hydroxyl groups, not entirely but only partially, i.e., in a
less-than-stoichiometric ratio, with alkoxysilyl terminal groups,
the alkoxysilanes being linked to the polymer, however, by chemical
bonding. The mixture thus formed, which accordingly contains both
hydroxyl groups and alkoxysilyl terminal groups, can be set not
only by moisture but also by the action of heat, while not only the
setting conditions but also the properties of the end product can
be varied widely by the appropriate selection of the starting
products. All that the products have in common is that the degree
of crosslinking of the end product can be determined as desired
through the silane content, without the occurrence of
incompatibility phenomena between crosslinking and non-reacting
polymer molecules.
The invention can be performed in a great variety of ways.
Fundamentally, a polymer which contains hydroxyl groups and is in
the liquid state at room temperature or moderately elevated
temperature (less than 100.degree. C.) serves as the starting
material. Especially suitable are polyester polyols, polyether
polyols, polyether ester polyols, functional glycerides and partial
glycerides (e.g., castor oil or ricinus monodiglyceride), or
hydroxyl groups containing polybutadienes and poly(methy)acrylic
acid ester copolymers.
Accordingly, the molecular weight of the starting products is less
than 20,000, and in most cases less than 10,000.
Only in the case of poly(meth)acrylic acid ester copolymers can
products with a molecular weight up to 30,000 be used.
The introduction of the alkoxysilanes into the polymer molecules
can be performed in various ways. One advantageous method consists
in the reaction of the named polymers with diisocyanates and those
organofunctional silanes which are capable of reaction with
isocyanates, one NCO group reacting with the silane and one with an
OH group of the polymer. Suitable for this purpose are especially
aminosilane esters, but also mercaptosilane esters and others with
sufficiently reactive hydrogens. The sequence of the reactions is
not critical, only care must be taken to assure that no unintended
increase of molecular weight takes place. Thus, the following
reaction sequences are alternatively possible:
(A)
Step 1: 1 mole of organofunctional silane+1 mole of
diisocyanate
Step 2: hydroxyl-containing polymer or polymer mixture+adduct from
Step 1 in such an amount that the OH:NCO ratio is less than
1:0.9.
(B)
Step 1: hydroxyl-containing polymer+diisocyanate, a molar ratio of
NCO:OH of close to 2:1 being selected to prevent undesired
molecular weight build-up.
Step 2: reaction of this prepolymer from Step 1 with a
stoichometric amount of an organofunctional silane ester named
above.
Step 3: Mixing of product from step 2 with hydroxyl-containing
polymer, so that the ratio of hydroxyl to alkoxysilyl groups is
equal to or less than 0.9. The polymer used for this purpose can be
either a starting product from Step 1 or another polymer of the
above-named group which is tolerable therewith.
Diisocyanates which are suitable are fundamentally all known
monomeric or polymeric diisocyanates which are available on the
market, it being possible to eliminate Step 1 of procedure B by
using a polymeric diisocyanate.
The use of triisocyanates is also basically possible. If they are
used, care must be taken to see that no undesired molecular weight
increase takes place.
Suitable organofunctional silanes are aminosilane esters of the
general formula: ##STR1## wherein: R.sub.1 =H or alkyl, cycloalkyl,
aryl, aralkyl or the moiety ##STR2## R.sub.2 =C.sub.1 -C.sub.5
alkylene R.sub.3 =methyl or ethyl
R.sub.4 =alkyl or alkoxyalkylene of up to 5 C atoms
n=0 or 1 or 2,
especially those having only one, preferably secondary, amino
group. The following are given as examples:
gamma-aminopropyltrimethoxysilane,
gamma-aminopropyltriethoxysilane,
N-methyl-gamma-aminopropyltrimethoxysilane,
N-cyclohexyl-gamma-aminopropyltrimethoxysilane,
N-n-octyl-gamma-aminopropyltrimethoxysilane,
N-phenyl-gamma-aminopropyltrimethoxysilane,
Di-[1-propyl-3(trimethoxysilyl)] amine,
N-methyl-gamma-aminopropylmethyl dimethoxysilane.
Mercaptosilane esters of the formula ##STR3## wherein R.sub.2,
R.sub.3 and R.sub.4 have the meaning given above, are also usable
in the practice of the invention, examples being:
gamma-mercaptopropyltrimethoxysilane,
gamma-mercaptopropyltriethoxysilane.
In addition to methoxy and ethoxy silanes, other alkoxy
substituents can be used, especially the monomethyl ethers of
glycols such as ethylene glycol or diethylene glycol etc.
After the products have been applied they can be set in a variety
of ways. For crosslinking by hydrolysis, it is especially
advantageous that, in the case of coatings, a large surface is, of
course, formed when a material is applied in a thin coat.
Accordingly, the crosslinking will take place even at room
temperature with atmospheric moisture. A substantial acceleration
can be achieved by appropriate hydrolysis catalysts known from the
literature, such as tin and titanium compounds or amines. A brief
treatment with hot steam is especially effective.
Crosslinking by the application of heat begins at about 100.degree.
C. and proceeds rapidly at temperatures above 120.degree. C. It is
also accelerated by suitable catalysts, such as dibutyl tin
dilaurate, for example, or other known transesterification
catalysts. It also helps to remove from the equilibrium the low
alcohols that are formed, unless this is accomplished
automatically, as easily happens when thin coats are applied.
While it is not advantageous in the case of hydrolysis hardening,
diols or polyols of low molecular weight can be used, in the case
of thermal setting, as chain lengtheners.
As already stated above, the choice of the molar ratio of hydroxyl
groups to alkoxysilyl groups covers a very wide range. In the case
of hydrolysis hardening, however, excessive crosslinking should be
prevented in order to avoid the disadvantages mentioned in the
beginning. In practice, therefore, a molar ratio of hydroxyl to
alkoxysilyl groups of 1.0 to 0.9 or less will be chosen, i.e., at
least 5 mol-% and not more than 90 mol-% of the hydroxyl groups of
the polymers will be replaced by alkoxysilyl groups. For the
thermal setting it can be assumed that one trialkoxysilane can
react with up to three hydroxyl groups, while a dialkoxy alkyl
silane can react with only up to two hydroxyl groups. It will
therefore not be difficult for the skilled art worker to establish
the desired degree of crosslinking. In general, therefore, a molar
ratio of hydroxyl to alkoxysilyl groups of 1:0.9 or less will also
be selected for thermal setting.
The products of the invention can, of course, be provided with
suitable inert diluents such as solvents, plasticizers, pigments
and fillers, if they have a sufficiently low moisture content so as
not to impair the shelf life of the preparations.
The products of the invention can be used in making adhesives,
especially hot-melt adhesives and structural adhesives, as well as
coatings such as cold- or hot-sealing coatings and varnishes,
especially the so-called high-solid varnishes.
The practice of the invention will be described in detail in the
examples that follow, and with reference to the drawings
wherein:
FIG. 1 shows the effect of temperature on hardening behavior,
FIG. 2 shows the effect of hardener concentration on viscosity
behavior and
FIG. 3 shows the change in consistency with time.
EXAMPLES
A. Components used
1. Polyesters
The following polyesters were prepared from the dicarboxylic acids
and glycols:
______________________________________ PES 1 PES 2 PES 3 PES 4
______________________________________ Composition: (in mol-%)
Terephthalic -- -- 35 -- acid Isophthalic -- -- 35 -- acid
Orthophthalic -- -- -- 79 acid Adipic acid 100 100 30 21 Ethylene
glycol 56 54 -- 21 Neopentyl 14 14 83 79 glycol Hexanediol-1,6 30
29 -- -- Trimethylol- -- 3 17 -- propane Properties: Glass tran-
-59.degree. C. -56.degree. C. +17.degree. C. +10.degree. C. sition
temp. Molecular wt. 2000 approx. 2000 1700 3000 Hydroxyl No. 55 35
95 60 ______________________________________
2. Polyester mixtures
The following mixtures were prepared from the polyesters listed
under 1:
______________________________________ PES-M 1 PES-M 2 PES-M 3
______________________________________ Composition: (in wt.-parts)
PES 1 100 -- -- PES 2 -- 100 40 PES 3 100 -- 100 PES 4 -- 25 --
Properties: Glass tran- -38.degree. C. -49.degree. C. -16.degree.
C. sition temp. Hydroxyl No. 76 43 77 Viscosity, mPa.S 25.degree.
C. 319,000 90,600 11,660,000 80.degree. C. 3,150 2,790 22,800
______________________________________
3. Polyethers
Of the great number of commercially available polyethers, a
polyetherol sold by BASF under the trademark name "Luphen U 1220"
was used. This product is a branched polypropylene glycol with a
functionality of 3, hydroxyl number 32 to 36 and an average
molecular weight of 4900.
4. Preparation of the hardeners
The term "hardener", as used hereinbelow, is to be understood to
mean the component of the resin which contains the alkoxysilyl
terminal group.
4.1 Adduct obtained from
3-isocyanatomethyl-3,5,5,-trimethylcyclohexylisocyanate (also
called isophorone diisocyanate and abbreviated IPDI hereinbelow)
and N-methyl-gamma-aminopropyltrimethoxysilane (Hardener 1).
In a 1000 ml three-necked flask with internal thermometer, stirrer
and dropping funnel, 334 g of IPDI and 75 g of WITAMOL 600 (polymer
plasticizer on a polyester base, mol. wt. 492, OH number 10 or
less, mfd. by Dynamit Nobel AG) were placed. The content of the
flask was cooled with an ice bath and the aminosilane was added
drop by drop such that the temperature of the flask contents did
not rise above 40.degree. C.
After a total of 290 g had been added, stirring continued for
another 10 minutes and then the NCO content was determined by
titration pursuant to DIN 53,185.
Theory: 9.05% NCO. Found: 9.91 to 9.3%.
The product obtained is a colorless liquid with a viscosity of
3,730 mPa.sec. at 25.degree. C., having good shelf life if moisture
is excluded.
4.2 Adduct prepared from IPDI and
N-methyl-gamma-aminopropylmethyl-dimethoxysilane (Hardener 2).
This product was prepared in a manner entirely similar to that
described under 4.1 and it also is stable when stored with the
exclusion of moisture.
Theory: 9.40% NCO. Found: 9.5%.
4.3 Adduct prepared from IPDI and
N-cyclohexyl-gamma-aminopropyltrimethoxysilane (Hardener 3).
This adduct can also be prepared by the method described above and
is stable when stored with the exclusion of moisture.
Theory: 8.7% NCO. Found: 8.7%.
4.4 Adduct prepared from IPDI and
N-n-octyl-gamma-aminopropyltrimethoxysilane (Hardener 4).
This adduct can also be prepared by the method described in 4.1 and
is stable when stored with the exclusion of moisture.
4.5 Adduct prepared from toluyl diisocyanate (TDI) and
N-methyl-gamma-aminopropyltrimethoxysilane (Hardener 5).
This adduct was prepared only from the components listed above,
without dilution by polymer plasticizers. Even with the exclusion
of moisture it keeps for no more than a few days, and immediately
after preparation it was reacted with one of the above-described
polymer mixtures containing hydroxyl groups.
Theory: 11.44% NCO. Found: 11.5%.
4.6 Adduct prepared from methylene-bis-phenylisocyanate (MDI) and
N-methyl-gamma-aminopropyltrimethoxysilane (Hardener 6).
This adduct was prepared as in 4.5 without plasticizer. It is not
stable in storage and was reacted immediately as in 4.5.
Theory: 9.5% NCO. Found: 9.6%.
4.7 Adduct prepared from PES 1 and Hardener 1 (Hardener 7).
500 g (i.e., approx. 0.25 mol) of PES 1 and 0.2 ml of dibutyltin
dilaurate (DBTL) were placed in a 1000-ml three-necked flask with
internal thermometer, stirrer and dropping funnel in a dry nitrogen
gas atmosphere and heated at 70.degree. C. 285 g (approx. 0.6 mol)
of Hardener 1 was added drop by drop, with stirring, and the
progress of the reaction was followed by titration (NCO titration
per DIN 53,185).
After about 3 hours the NCO content had dropped to 0.49% and no
more free hydroxyl groups were available, and the reaction
ended.
The product obtained in this manner is colorless and has good
stability in storage with the exclusion of moisture.
Viscosity at 25.degree. C. approx. 600,000 mPa.S.
Viscosity at 80.degree. C. approx. 7,000 mPa.S.
4.8 Adduct prepared from PES 2 and Hardener 1 (Hardener 8).
By a procedure similar to that described in section 4.7, a
hydroxyl-group-free adduct was prepared from 800 g of PES 2, 0.2 ml
of DBTL and 250 g of Hardener 1. This product is still more viscous
than Hardener 7 and has only a limited shelf life.
4.9 Adduct prepared from IPDI and
N-methyl-gamma-aminopropyl-tris(methoxydiglycol) silane (Hardener
9).
The adduct was prepared from 33.3 g (0.15 mol) of IPDI in 5.0 g of
WITAMOL 600 and 68.55 g (0.15 mol) of
N-methyl-gamma-aminopropyl-tris(methoxydiglycol)-silane by a
procedure similar to that described in 4.1.
Theoretical NCO content: 6.0%. Found: 6.3%.
4.10 Adduct prepared from IPDI and gamma-mercaptopropyl-silane
(Hardener 10).
22.2 g (0.1 mol) of IPDI and 0.1 g of DBTL were placed in a 100 ml
Erlenmeyer flask and heated at about 60.degree. C. A total of 19.0
g (0.1 mol) of gamma-mercaptopropylisilane was added in small
portions, while stirring with a magnetic stirrer, and the mixture
was allowed to react for a total of 3 hours.
Theoretical NCO content: 10.1%. Found: 10.4%.
4.11 Adduct prepared from methylene-bis-phenylisocyanate (MDI) and
gamma-mercaptopropylisilane (Hardener 11).
270 g of an MDI with an equivalent weight of 135 (instead of the
theoretical value of 125 for pure MDI) was placed in a dry nitrogen
atmosphere in a 1000 ml three-necked flask with internal
thermometer, stirrer and dropping funnel, and heated at 70.degree.
C., and 190 g (1.0 mol) of gamma-mercaptopropylsilane was added
drop by drop. After 2 hours the reaction had ended. The product is
unstable in storage.
Theoretical NCO content: 7.9%. Found: 6.6%.
4.12 Adducts prepared from Luphen 1220 (polypropylene glycol; see
section 3) and Hardener 1.
Two adducts were prepared as follows:
4.12.1 Molar ratio of Luphen 1220 to Hardener 1 (for purposes of
comparison), 1:3, i.e., stoichiometrically complete.
120 g of Luphen (0.0245 mol)
34.3 g of Hardener 1 (0.0735 mol).
4.12.2 Molar ratio of Luphen 1220 to Hardener 1:1:2.
120 g of Luphen (0.245 mol)
22.8 g of Hardener 1 (0.049 mol).
These mixtures were reacted each in a dry nitrogen atmosphere at
70.degree. C., with catalysis by 0.2 g of DBTL. After 2 hours of
reaction, the reaction had completely ended so that no more free
--NCO could be detected.
5. Examples of the hardening of the mixtures of the invention.
5.1 Effect of temperature on hardening.
The components described above were mixed at 80.degree. C. and the
viscosity increase was measured at different temperatures in a
Rheotron rotation viscosimeter (plate-and-ball combination P
10):
Polyester mixture PES-M 1 100 weight-parts,
Hardener 1 5 weight-parts,
DBTL 0.3 weight-parts.
The results are represented in FIG. 1 and they show that at
100.degree. C. this mixture shows a barely perceptible viscosity
increase, and accordingly can still be worked easily at this
temperature.
At temperatures above 130.degree. C., the hardening takes place
rapidly and at temperatures above 120.degree. C. it still is
completed in only a few minutes.
5.2 Effect of hardener concentration on viscosity at constant
temperature.
In the same experimental arrangement as described in 5.1, the
influence of the amount of hardener at 130.degree. C. was tested,
using 3, 4, 5, 8 and 12 parts of hardener 1 for 100 weight-parts of
PES-M 1 and 1 part of DBTL. The results are represented in FIG.
2.
5.3 Hydrolytic setting
Two weight-parts of polyester mixture PES-M 1 and one weight-part
of Hardener 7 were mixed at 80.degree. C. in a Brabender
Plastograph, and the stoichiometric amount of water needed for the
complete hydrolysis of Hardener 7 was added. The increase in
consistency with advancing hydrolysis is represented in FIG. 3.
It will be understood that the specification and examples are
illustrative but not limitative of the present invention and that
other embodiments within the spirit and scope of the invention will
suggest themselves to those skilled in the art.
* * * * *